/*
 * Cursor.h
 *
 * This source file is part of the FoundationDB open source project
 *
 * Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef _CURSOR_H_
#define _CURSOR_H_

#pragma once

#include "QLPlan.h"

struct Cursor : ReferenceCounted<Cursor>, NonCopyable {

	FutureStream<Reference<ScanReturnedContext>> docs;
	Reference<PlanCheckpoint> checkpoint;
	int64_t id;
	int32_t returned;
	std::map<int64_t, Reference<Cursor>>* siblings;
	time_t expiry;

	Cursor(FutureStream<Reference<ScanReturnedContext>> docs, Reference<PlanCheckpoint> checkpoint)
	    : docs(docs), checkpoint(checkpoint), returned(0) {
		id = g_random->randomInt64(INT64_MIN, INT64_MAX);
		expiry = time(nullptr) + DOCLAYER_KNOBS->CURSOR_EXPIRY;
		siblings = nullptr;
	}

	void refresh() { expiry = time(nullptr) + DOCLAYER_KNOBS->CURSOR_EXPIRY; }

	static int32_t prune(std::map<int64_t, Reference<Cursor>>& cursors);

	static void pluck(Reference<Cursor> cursor);
	static Reference<Cursor> add(std::map<int64_t, Reference<Cursor>>& siblings, Reference<Cursor> cursor);
};

#endif /*** _CURSOR_H_ */
